In enterprise data systems, it is very important to prevent downtime. Such downtime may be caused by scheduled maintenance or unpredicted system or component failure, e.g., failure of one or more of a server, processor, network, storage, database etc. To prevent downtime, systems are designed with failover options, i.e. the ability to switch between a primary system component and a secondary system component.
Currently, storage replication, especially synchronous storage replication, is primarily used by applications which need instant failover. Replication is a managed service in which stored or archived data is duplicated in real time over a storage area network (SAN). Replication helps in maintaining continuity of data access in a network and also helps in disaster recovery.
Currently available synchronous implementations, such as, host/appliance or array based replication, are very slow and not suitable for applications which have very high write bandwidth requirements.